Conversion of glucose to ATP

1. Overview 2. Purpose: To Get ATP! 3. Electron Carrier Molecules 4. Mitochondria 5. The Basics of Cell Respiration 6. Glycolysis 7.Pyruvate chemical “grooming” 8. Kreb’s Cycle 9. Electron Transport Chain (Oxidative

Phosphorylation) 10. Cell Respiration Summary 11. Fermentation- Anaerobic Respiration

Who does it?All living things: both autotrophs and heterotrophs

What is it?Carbohydrates and O2 are used to make ATP

(energy). CO2 and H20 are waste products.Involves three steps: glycolysis, kreb’s cycle, and

electron transport chain.The opposite of photosynthesis.

Where does it occur?The cytoplasm and the mitochondria of the cell

Cellular respiration releases energy by breaking down glucose and other food molecules in the presence of oxygen.

Equation: C6H12O6 + 6O2 6CO2 + 6H20 + ATP Glucose+ oxygen carbon dioxide + water +

energy

ATP: A modified nucleotide molecule that powers all cellular work directly.

Phosphorylation When ATP releases a phosphate + energy

it produces ADP (adenosine diphosphate) ADP can turn back to ATP by taking in a

phosphate and energy by phosphorylation Similar to recharging a battery

There are two different molecules that are used to carry electrons and hydrogen ions to the last step cellular respiration. NADH- NAD+ FADH2- FAD

Cellular respiration takes place in small steps to minimize the loss of energy in the form of heat or light.

Processes that require oxygen to take place are called aerobic.

Processes that do not require oxygen to take place are anaerobic.

Aerobic Cellular respiration consists of three major steps (when oxygen is present): Glycolysis – occurs in the cytoplasm The Krebs cycle – occurs in the matrix of

mitochondrion Electron transport chain – occurs along the

innermembrane in the cristae of mitochondrion

Means “splitting sugar” Occurs in the cytoplasm Is anaerobic (doesn’t require oxygen) Glucose (6-C) is split to two molecules of

another organic compound, called pyruvate (3-C).

Makes 4 ATP, but uses 2 ATP, for a net gain of 2 ATP ATP can be used by cell immediately

A net gain of 2 NADH molecules NADH must pass down the ETC in mitochondria

Water is released as waste product

As pyruvate forms at the end of glycolysis, it is transported from the cytoplasm into the mitochondria

Pyruvate does not enter the Kreb’s Cycle as itself.

It undergoes major chemical “grooming”

A carbon atom is removed from pyruvate (3-C) forming acetyl coA (2-C)

NADH molecules are made (per pyruvate-3C) CO2 is released as a waste product (per pyruvate-

3C)

Occurs in the matrix of the mitochondria Compared with glycolysis, Kreb’s Cycle pays big energy

dividends to the cell This makes 1 ATP, 3 NADH and 1 FADH2, per acetyl coA

(2-C) (double that for each glucose molecule) Releases CO2 as waste is aerobic (requires oxygen)

Occurs along the inner membrane of the cristae of the mitochondria

NADH and FADH2 from glycolysis and Kreb’s Cycle give up their H+ and electrons to make ATP 3 ATP for each NADH and 2 ATP for each FADH2

O2 is the final electron acceptor and becomes water which is a waste product

Is aerobic and makes most of the energy in cell respiration.

TOTAL= 38 ATP (theoretical) Glycolysis

Occurs in cytoplasm 2 ATP 2 NADH 2 H20 get released 2 pyruvate

Kreb’s Cycle (including pyruvate grooming) 2 ATP 8 NADH 2 FADH2 6 CO2 get released

Electron Transport Chain H20 gets released 10 NADH get converted to 3ATP= 30 ATP 2 FADH2 get converted to 2 ATP= 4 ATP

Glycolysis is the metabolic pathway that generates ATP during fermentation.

No O2 is required; it generates a net gain of 2 ATP and 2 NADH

Significantly less ATP is generated, but it is enough to keep your muscles contracting for a short while when the need for ATP outpaces the delivery of O2 via the blood stream

Many microorganisms supply all their energy needs with the 2 ATP yield of glycolysis.

Fermentation provides an anaerobic step that recycles NADH back to NAD+; essential to harvest food energy by glycolysis.

Two types of fermentation: Lactic acid Alcohol

Lactic acid fermentation 1. Glycolysis occurs 2. NADH is recycled to NAD+ as pyruvate

becomes to lactic acid.

Lactate builds up in muscle cells during strenuous exercise is carried in the blood to the liver, where it is converted back to pyruvate

Dairy industry use this to with bacteria to make cheese and yogurt

Alcohol fermentation 1. Glycolysis occurs 2. NADH is recycled to NAD+ while pyruvate (3-

C) releases a CO2 and becomes ethanol (2-C) (ethyl alcohol).

Used by yeasts and bacteria Used in brewing, winemaking, and baking CO2 provides bubbles in beer and champagne,

and bread dough to rise Ethanol is toxic to organisms that produce it;

must release it to their surroundings